Fun-guys Flashcards
Where are fungi found
Ubiquitous in environment; decay, mold
Skin and mucous membranes: host adapted or contaminants from environment
What are characteristics of fungi?
Eukaryotes
Free living
Saphophytes (majority)
Heterotrophs (obtain carbon by consuming organisms)
Asexual reproduction, buddin through spores
Cell membrane contains terrors (ergosterol)
Plant like cell wall with gucan, mannan, and chitin
A unicellular mold is called
Yeast
Multicellular fungis are called
Molds
What are the fruiting bodies of a mold
Spores
Group of tangled hyphae is called
Mycelium
Morphology of yeast
Colony - opaque creamy smooth
Microscopic - round single cells
Morphology of molds
Colony- woolly, fluffy, powdery
Micro- tube like multicellular structures forming mycelium
Dimorphic fungus morphology
Both opaque and smooth colonies or woolly-fuffly
Yeast or hyphae depending on temp
The growing form of the fungus is
Hyphae
Dark pigmented hyphae are called?
Dematiaceous fungus
Non pigmented fungus is called
Hyaline
A hyphae that is divided by cell walls is called
Septate
__________ is when fungal contamination or growth on food material leads to accumulation of toxins and when consumed willl induce disease
Mycotoxicoses
__________ is when fungal spores are inhaled and induce hypersensitivity
Allergy
Environmental fungal organisms infects who mainly?
Immunocompromised
T/F: fungal infections usually induce chronic granulomatous infection
True
Superficial fungal infections are limited to?
Outermost layers of skin and hair
Cutaneous fungal infections are localized where?
Deeper into epidermis and are invasive to hair and nails
Why do we have few antimicrobial agents to treat fungus?
Fungus is eukaryotic, usually anything that targets them will also target the host –> need to find very specific targets
Subcutaneous fungal infections are localized where?
Dermis, and subcutaneous tissue , muscle and fascia
__________ fungal infections usually originate in the lungs but spread to many other organisms
Systemic
What are ways to diagnose fungal disease
Morphological recognition
-cytology, histopatholgoy, wet mount
Clinical specimens
-Beta D-glucan assay (general component of cell wall)
Host immune resposne
-agar gel immunodiffusion, ELISA
Culture and ID
PCR
What sp most commonly get crytococcus infection
Cats
Minnie mitten
Simon Norman
What is the routine stain used for histopathology of fungus
H and E
Yes or no there is a fungus
What is used to find ringworm ?
KOH on hair
Chitin is stained by ?
Calcoflour -> need UV microscope
How do you culture fungus
Special medial and growth cond
Low temp under aerobic conditions
Fungal medial
Sabouraud dextrose agar (classic fungal medium)
Sabouraud dextrose with cyclohesimide -> inhibit saprophytic mold -> see only pathogenic fungi
Low pH
How are fungus identified
Growth characteriris Microscopic appearance Biochemical characteristic Hyphae characterisitic Type of asexual sporulation Characteristics of spores
What is the main antifungal drug we use ?
Polyenes - inhibit ergosterol
Amphoterocin B
Griseofluvin has antifungal activity by inhibiting what?
Mitotic spindles -> mitosis
Accumulate in keratin layer -> for ringworm (dermatophytosis)
Oral
Polymers, anoles, and allylamines all inhibit__________
Ergosterol
Antifungal susceptibility tests
Broth dilution
Disk diffusion
Few labs
Interpretive breakpoints for only a few drugs
Most fungal lesions are ???
Granulomatous
What immune reponse does the host produce against fungus?
Extracellular - Ab (usually not productive)
Intracellular -cell mediated
Most fungus are extracellular but can invade macrophages
What are dermatophytes?
Superficial mycosis (ringworm or tinea) Keratinotrophic
Are dermatophytes invasive?
Generally noninvasive, superficial infection
Who is predisposed to dermatophytosis?
Youth Poor nutrition High humidity Rubbing Low UV light (fall/winter in cattle)
Highly contagious!
T/F: dermatophytes are zoonotic
True
What are the common dermatophytes ?
Microsporum canis, M.audouinii, M.gypsium (dog, cat, human) Microsporum nanum (pig)
Trichophyton mentarrophytes (broad host range) Trichophyton verrucosum (cattle) Trichophyton equinum (horses)
What is ringworm? And what are the classic lesions?
A non-invasive benign infection that is highly contagious caused by dermatophytes
Slowly expanding circular area of alopecia and desquamated epithelium
Central hair regrowth, inflamed edge. Opens multiple sized lesions
Trichophyton verrucosum causes _________ in what species
Ringworm ; cattle
Ringworm in cats and dogs are usually caused by what dermatophytes?
Microsporum canis
Microsporum gypsium
What dermatophytes has a wide host range?
Trichophyton mentagrophytes
___________________ is a nodular lesion caused by dermatophytes, which is a localized/generalized folliculitis
Kerion
_____________ is a subcutaneous nodule caused by microsporum canis
Pesudomycetoma
How is ringworm diagnosed?
Clinical species ID
Woods lamp detection -> fluorescence (M. Canis)
Wet mount with 10% KOH -> see spores (ectothrix or endothrix for species ID)
How should you collect a sample for testing dermatophytosis?
Disinfect the area with 70% alcohol
Use forceps for hair
Scalpel blades for tissue
Curette for nails
Clean pill pack or small container with loose cap (decrease
Culture media-> directly inoculated
What stain do you use for dermatophytes?
Lectophenol cotton blue staining
T/F: fungi are always multicellular
False
What causes avian ringworm?
Microsporum gallinae (favus)
Yeast - unicellular
Mold- multicellular
How do you treat ringworm?
Spontaneous recovery Hygiene, environmental treatment Isolation Clip hair Wash/sprays - lime sulfur, sodium hypochlorite, chlorhexidine, povidone-iodine
Azol (ketoconazole, itraconzole, miconazole ect..)
Natamycin
Terbinafine
Grisofluvin
Mycolic acid is found in _________
Mycobacterium
What is the MOA of Griseofulvin and what is the ONLY fungal infection that they treat?
Accumulate in keratinocytes and inhibits fungal DNA synthesis
Dermatophytes
Are vaccines available for ringworm?
Yes in Cat and Cow!
Ketoconazole is and enzyme (inducer/inhibitor). What might this mean for other drugs
Inhibitor.
Prolonged half life..
What a pharmacology question in the mycology course? how dare you!
What are the three groups of dermatophytes?
Anthropophilic- human reservoir
Zoophilic -animal reservoir
Geopolitical- soil/environment reservoir
Folliculitis can be a non-classic lesion of ringworm in dogs, these can b due to secondary infections.. what is most likely the bacteria?
Streptococcus pseudintermedius #tbt
T/F: woods lamp only is effective to find one species of dermatophytes?
True
Mycosporum canis
Who is the asymptomatic carrier of microsporum canis
Kitty kitty cat
Now you cant keep your Baileys with your Simons and Minnies…
